Unless there is a major disruption, in 50 years we will have hit hard the limits of earth natural resources (in terms of metals/minerals/oil) and the consequences of climate change so it's very difficult to predict how the world will be. My guess is that once the system reaches some kind of new equilibrium, jobs will be mostly low-tech and very similar to 1 century ago : farmers (with permaculture), bakers, people who repair stuffs, blacksmiths (but with far less volume of production compared to the industrial world we live in today and mostly simple/repairable/low-techs stuffs : hammers, bikes, shovels, plows...).